Borehole data transmission system

ABSTRACT

The particular embodiment described herein as illustrative of one form of the invention utilizes an instrument system for detecting the angular position and directional orientation of a housing within a wellbore and for generating signals indicative of such information. These signals are stored in binary form and then coded for transmission to the surface over a conductor which also carries the power supply for the system. At the surface the signals are decoded to provide data indicative of downhole information.

United States Patent 11 1 3,699,510

Lindsey 1 51 Oct. 17, 1972 [54] BOREHOLE DATA TRANSMISSION 2,679,7576/1954 Fay ..340/l5.5 CM SYSTEM 3,427,580 2/1969 Brock ..340/15.5 CM

[72] Inventor: James M. Lindsey, Houston, Tex. Primary Examiner BenjaminA Borcheh [73] Assignee: Sperry Sun Well Surveying Com- AssistantExaminer-N. Moskowitz pany, Sugar Land, Tex. Attorney-George L. Church,Donald R. Johnson, [22] Filed: No 21, 1969 W1lmer E. McCorquodale, Jr.and John E. Holder [211 Appl. No.: 879,011 [57] ABSTRACT The particularembodiment described herein as illus- [52] U.S. Cl ..340/l8 CM "alive ofone form of the invention utilizes 51] 1111. C1. ..G0lv 1/22 ment Systemfor detecting the angular position and [581 Field of Search ..340/15.sCM, 18 CM directional Orientation of a housing within a Wellbore and forgenerating signals indicative of such informa- 56] References Citedtion. These signals are stored in binary form and then coded fortransmission to the surface over a conductor UNITED STATES PATENTS whichalso carries the power supply for the system. At

the surface the signals are decoded to provide data in- R25,209 7/1962Kolb ..340/1S.5CM 3,103,644 9/1963 Burton ..340/1s.sc1v1 came 3,015,8011/1962 Kalbfell ..340/ 15.5 J 35 Claims, 8 Drawing Figures 6 2ELECTRONIC SECTION DIRECTIONAL I 7-GYRO SYSTEM GYRO -ToRouE CONTROLPATENTEDUBI 17 I972 ELECTRON|C SECTION FIG.

ANGLE |2-*DETECTING UN ITS DIRECTIONAL I 7*GYRO SYSTEM GYRO 22-TORQUECONTROL SHEET 1 BF 5 LINE FROM LINE SUBSURFACE SYNC PULSE POWER BITPULSE I37 2 K J I M WAVE ggg g' g f DATA REJECTION PROCESSING CIRCUITCIRCUIT SYNC DATA SHIFT REGISTER STORAGE 5 PE'IZER CLOCK COMPUTER (WAVESHAPE CIRCUIT) //VVE/V70R JAMES M. LINDSEY ATTORNEY PATENTEDUCT 17 I972SHEET 2 BF 5 IOO FIG 3 FIG. 2

INVENTOR JAMES M. LINDSEY ATTORNEY UN 1 7 I972 O SHEET '4 OF 5 I33 SCANSCAN SCAN SCAN IIB/ ESET BIT I BIT I5 BIT l6 H7 1 s I H6 L w SCAN l IIH6 DRIVE I32 I27V BIT BIT BIT S I I5 I6 DRIVE GATE GATE GATE '2' l V ABcT AB CT ABcT WORD SELECT STOIQIEM STOI E sToT E PENDULUM I l I5 I6 Tf'T T WORD GATE COUNT COUNT COUNT L M I I5 l6 PENDULUM I I d STORE COMMANDPENDULUM l GATE DRIVE g' WORD sEI EcT HI PENDULUM I PENDULUM 2 COUNTRESET WORD GATE B|T B|T PENDULUM I I6 2 GATE GATE A B ABC I PENDULUM 2GATE DRIVE 2! ST(|)RE STgRE STPGRE WORD SELECT TI T T GYRO COUNT COUNTCOUNT I l5 l6 PENDULUM 2 WORD STORE GATE COMMAND GYRO PENDULUM 2 GYROGATE DRIVE COUNT RESET //VVE/VTO/? AMES M. LINDSEY FIG 5 ATTORNEYPATENTEDHBT I 1 I912 3599.51 0

SHEET 5 OF 5 GATE LINE DRIVE POWER I33 SCAN LINE BIT I6 I34 l II6 I22 Ii f GATE 7 LINE BIT Im I32 INSERT BIT f t" s GATE j H? scAN DRIVE A BCII4 A A V I27 sToRE /l26 '6 WORD BIT T GATE FILTER DRIVE COUNT I6 I2Iw0RD SELECT a; PENDULUM I woRD GATE PENDULUM |3| S PENDULUM L U GATEDRIVE J v I Z scAN H8 REsET woRD SELECT I PENDULUM 2 WORD GATE PENDULUMV 7 U SYNC PENDULUM 2 PULSE GATE DRIVE 1 INSERT woRD SELECT GYRO FIG 6I/VVE/VTOR JAMES M. LINDSEY GYRO GATE DRIVE A TTORNEY BOREIIOLE DATATRANSMISSION SYSTEM BACKGROUND OF THE INVENTION traverse of earthformations. It is for this reason that various apparatus and methodshave been devised for making such determinations of borehole attitude.Normally such systems consist of apparatus for measuring the angulardisposition of the hole with respect to some reference such ashorizontal reference plane, and in addition, means for determining thedirection of the hole with respect to a reference such as MagneticNorth. A typical apparatus for making such determinations of a boreholeposition consists of an instrument unit, in-

- cluding a compass or a gyro, together with an angular unit having aplumb-bob arrangement, and a photographic device of some sort for makinga photographic recording of the instruments in the wellbore. In thepast, these instruments have been run on wirelines or go-deviled intothe drill pipe where they are subsequently retrieved as in the lattercase, by removing the drill pipe from the borehole. Upon retrieval ofthe instrument to the surface, the photographic equipment is removed andthe exposed film record of the instrument recordings is then removed toa suitable location for developing the film. Thereafter, if calculationsare to be made regarding the orientation of the borehole, suchinformation derived from the film can then be utilized in computationequipment for making such determinations. In any event, the procedureoutlined above is time consuming, and if decisions for continuingdrilling or for making changes in the orientation of the wellbore arerequired, then such decisions must be held in abeyance until the film isdeveloped and computations can be made from the indicated parameters ofthe well borehole. In other borehole instrument system, multipleconductor cables are used to power instruments and transmit data to thesurface representative of the instrument functions. The number ofconductors of course is determinative of the size and cost of conductorlines and a single conductor cable is preferable for these reasons.

It is therefore an object of the present invention to provide a new andimproved system for transmitting logic from a borehole apparatus to thesurface.

SUMMARY OF THE INVENTION With this and other objects in view, thepresent invention contemplates a system for use in a borehole within theearth for detecting and sending signals to the surface, which signalsare indicative of a parameter within the borehole.

The downhole apparatus may be comprised of separate units for detectingdifferent parameters such as those associated with the orientation ofthe borehole. Such units provide signals indicative of detectedparameters for transmission to the surface. The present inventionutilizes means for storing data downhole representative of variousdetected parameters and sequencing such data for insertion on aconductor for transmittal to the surface. The data information isdecoded at the surface, resequenced, and supplied to a computer orreadout equipment for use in calculating conditions dependent upon suchparameters.

A complete understanding of this invention may be had by reference tothe following detailed description, when considered in conjunction withthe accompanying drawings, illustrating embodiments thereof.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of awellbore tool including instruments for measuring angular and azimuthalparameters of the tool position;

FIG. 2 is a partial cross-sectional view of a wellbore instrument formeasuring the angular orientation of the instrument within the wellbore;

FIG. 3 is a partial cross-sectional view of a wellbore instrument formeasuring the directional orientation of the instrument within thewellbore;

FIG. 4 is a schematic circuit diagram showing a system for convertinginstrument data to digital pulses and counting and storing such data;

FIG, 5 is a schematic circuit diagram showing a system for reading outthe stored data from the instrument section for transmission to thesurface;

FIG. 6 is a schematic circuit diagram showing an extension of the systemin FIG. 5 for coding such data for transmission to the surface;

FIG. 7 is a schematic drawing depicting waveforms and pulses as theyappear on the above circuits; and

FIG. 8 is a schematic circuit diagram showing surface equipment fordecoding the data and processing same to obtain wellbore information.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The data transmission systemwhich is the subject of this invention is described in conjunction witha borehole tool for detecting positional parameters of an instrumentwithin a borehole, and transmitting such data to the surface. There thedata is processed and recorded in a form permitting a direct read-out ofborehole orientation.

FIG. 1 shows a schematic of such a wellbore tool which includes an angledetecting section 12 having first and second angle detecting units 13and 14 mounted therein to measure the angular disposition of planes insection 12 which are to one another. A synchronous motor 16 ispositioned between the units to provide a source of power for drivingscanning systems within the units to thereby monitor parameters of thedetecting units which are indicative of their angular disposition. Themotor 16 has output shafts extending upwardly and downwardly therefromto drive the respective scanning systems for the first and second units13 and 14. A directional section 17 is positioned below the angledetecting section and includes mechanisms for measuring the directionalorientation of the housing relative to the earths surface. Thedirectional section 17 incorporates a gyroscope 18, a gyro motor 19, andan encoder 21 for providing a reference signal to the detecting units. Alower section 22 houses a gyro torque motor 23 and a torque motorcircuit 24 for controlling precessing of the gyro. An upper electronicsection 26 of the tool houses an electronic scanner circuit and datacounter and storage units.

An angle detecting unit for generating signals indicative of the angularposition of the instrument within the borehole is shown in detail inFIG. 2 of the drawings. The angle unit includes a partially enclosedhousing 27, having the synchronous motor 16 mounted at its upper end.The motor has an output shaft driven at 3,600 rpm. Between thesynchronous motor and housing is mounted a transmission or gearreduction section 29 which has two stages of pinon gears connected withthe output shaft 28 of the synchronous motor for reducing the outputrevolution thereof. The output'of the gear reduction section is fedthrough a shaft 31 which extends longitudinally from the upper to thelower end of the instrument housing. At the lower end of the outputshaft, a worm gear 32 is rotated therewith for driving s spiroid gear33, which in turn drives a scanning system within the instrument. Thetotal gear reduction between the output of the synchronous motor and therotation of the spiroid gear within the instrumenthousing is from 3,600rpm of the motor to 20 rpm of the spiroid gear 33.

The angle detector and scanning system are located within the housingand include a horizontal shaft 36 extending transversely across thehousing midway between its ends. A scanner assembly is rotatably mountedabout the left side of the shaft as viewed in FIG. 2, and is providedwith bearings 37, 38 for rotatably supporting the assembly about theshaft. The scanner assembly is comprised of a large diameter verticaldisc 39 upon one side of which is mounted the circular spiroid gearsection 33. The spiroid gear is arranged to mesh with the worm gear 32on the shaft 31 extending vertically through the housing. A sleeve 41extends outwardly from the vertical disc 39, and is positioned about thehorizontal shaft 36. An insulating cylinder 42 is positioned about thesleeve. Grooved commutator rings 43 are positioned about the insulator.The grooved commutators are electrically insulated from one another toprovide separate electrical flow paths between the stationary portion ofthe instrument housing and the rotating scanner section. An insulatingpost 44 is positioned above the commutators and is connected to the sidewall of the housing. Brushes 46 extend downwardly from the post intocontact with the commutators. The upper ends of the brushes areconnected to terminal posts 47 to provide a means for electricallyconnecting the brushes with conductor wires (not shown) within theinstrument hous- Referring again to the vertical disc 39 of the scannersection, a lamp 48 and lamp housing 49 are shown extending outwardlyfrom the outer rim of disc 39 toward the center of the housing. A firstslit 51 is formed in the outer wall of the lamp housing and isperpendicular to the shaft 36. A second slit 52 is formed along thebottom portion of the lamp housing 49 and is parallel with the shaft 36.A detector photocell 53 and housing 54 are mounted on the disc 39 andextend outwardly from the disc on the same side as the lamp 48 andhousing 49. Wires (not shown) extend from the photocell through the discand into contact with the commutator rings. The photocell housing has aslit or opening 56 in its upper side wall and parallel to the shaft 36to permit light emanating from lamp 48 to project into the housing foractivating the photocell. Conductor wires are also provided to the lamphousing from the commutator rings to provide an electrical power sourceto the lamp.

A pendulum assembly is also mounted ,on the horizontal shaft 36 oppositethe scanner assembly. The pendulum assembly is comprised of an annularsleeve 57 positioned about the shaft and rotatably supported thereon bymeans of bearings at each end of the annular sleeve. A circular shield58 extends outwardly from the sleeve and includes an L-shaped portion 59extending inwardly therefrom toward the circular disc 39 of the scannersection. The inwardly extending portion 59 of the shield approachescontact with the vertically mounted disc 39,, but does not contact thedisc, so that the pendulum assembly is free to move independently withrespect to the scanner assembly. The shield and its inwardly extendingportion are arranged to pass over and about the detector photocell 53and housing 54.

The inwardly extending portion of the shield passes between the bottomof the lamp housing 49 and the upper side of the photocell detectorhousing 54. A slit 61 is formed in the inwardly extending portion of thesleeve in parallel relationship with the slit 52 formed in the lowerside of the lamp housing. A weighted pendulum member 63 is connected totheshield 58 and covers a partial segment of the shield. This weightedpendulum member maintains the shield in an oriented position relative togravity, regardless of the position of the housing with respect togravity, since the pendulum assembly is freely mounted for rotation uponthe horizontal shaft 36. The slit 61 in the inwardly extending portion59 of the shield is positioned at a point thereon corresponding to apoint on the periphery of the weighted pendulum member 63 directly belowthe center of gravity of the weighted member when the member is at freerest relative to gravity.

Also mounted within the interior of the housing is a second or referencephotocell or other such light sensitive device 64, which is positionedat the upper end of the interior portion of the instrument housingopposite a point on the path of movement of the lamp 48. A vertical slit66 is provided within the outer wall of a photocell housing 67, whichslit is arranged to be oppositely disposed and parallel to the slit 51in the lamp housing 49. Conductor wires (not shown) provide anelectrical power source for the photocell 64.

In the operation of the apparatus just described, the synchronous motor16 is continuously driving the gear reducing mechanism to rotate thespiroid gear 33 and scanner disc at a rate of 20 revolutions per minuteor i revolution every 3 seconds. This means that the lamp 48 on thescanner disc 39 will pass in front of the reference photocell 64 on theinterior wall of the housing, once every three seconds. The lamp 48 iscontinuously energized. As a result, the reference photocell will beactivated to generate a signal once every 3 seconds for purposes to behereinafter described.

As the scanner disc and lamp continue to rotate during each revolution,a second signal is generated when the lamp 48 passes the slit 61 in theinwardly extending portion of the pendulum shield. The slit 61 permitslight from the lamp to impinge upon the detector photocell 53 which ispositioned on the scanner disc 39 next to'the lamp 48. The shieldnormally prevents the lamp from activating the photocell 53, except whenthe lamp and photocell pass the slit 61 in the pendulum once during eachrevolution of the disc. The slit in the shield is positioned relative tothe gravitational pull of the weighted pendulum member, so that eventhough the housing is tilted at an angle with respect to the vertical,the shield will remain in a constant position determined by the force ofgravity. Therefore, the slit 61 in the shield will always remain at thebottom (relative to earth's gravity) of the pendulum shield. As the lamp48 and photo detector cell 53, which are mounted on the scanner disc,move past the slit 61 in the pendulum shield at its lower side, thelight emanating from the lamp will pass through the slit and beprojected upon the detector photocell, which in turn generates a signalthat is picked up from the commutator rings and brushes for purposes tobe hereinafter described.

It is readily seen that as the scanning disc 39 rotates, a pulse isgenerated once every three seconds by the case reference photocell 64,and that a second pulse is generated at some time lapse after the firstcase reference photocell pulse is generated, depending upon the positionof the slit 61 in the pendulum shield relative to the case referencephotocell. If, for example, the instrument housing were lying in ahorizontal position with respect to the surface of the earth, thescanner, if operating in a clockwise direction, (as viewed from theright side as shown in FIG. 2) would generate a first signal when thelamp 48 passes the slit 66 in the case reference photocell housing. 90rotational degrees thereafter, the scanner would generate a secondsignal when the lamp 48 passes the slit 61 in the pendulum shield toactivate photocell 53. if the time rate of rotation of the scanning disc39 is known, then the actual number of degrees transgressed by thescanning mechanism between such first and second signals may becalculated.

In order to provide completely accurate information as to the angularposition of the instrument housing with respect to a vertical referenceplane, it is desirable to utilize the second angle detecting unit 14,which is mounted so that the scanning disc and pendulum shield of thesecond instrument are in a vertical perpendicular to that of the planeof the shield and disc in the first instance. As will be describedhereinafter, the data outputs of each of the pendulum instrumentsections is fed to a data processing unit where a vector summation ofthe outputs provides a true calculation of the angular disposition ofthe instrument housing.

Referring now to FIG. 3 of the drawings, details of I the directionalunit 17 (FIG. 1) are shown. Directional unit 17 provides informationrelative to the directional or azimuthal orientation of the instrumenthousing. The unit shown in FIG. 3 is very similar to that of FIG. 2 inthat a scanning section is rotated relative to a shield, which insteadof being oriented by a pendulum, is driven by the rotation of thevertical shaft 71 of the directional gyroscope 18. The vertical oroutput shaft 71 of the gyroscope is shown connected to a vertical sleeve73, which is press fitted onto the output shaft of the gyro. The sleevehas an outwardly extending shield portion 74 which in turn has anupwardly extending circular shield wall 76. The gyro instrument housing77 has a synchronous motor 19 and gear reduction section 79 mounted onits upper side, with the output shaft 81 of the gear section extendingthrough the top of the instrument housing 77 and downwardly into theinstrument. Bearings are provided in the top of the instrument housingto rotatably support the motor driven output shaft.

A scanning section is mounted on the motor driven output shaft forrotation within the instrument housing. The scanner section is comprisedof a vertical sleeve 82 attached to the lower end of the shaft. Thesleeve has an insulated cylinder 83 about its outer walls upon which aremounted commutator rings 84 which are electrically insulated from oneanother. At the lower end of the scanner sleeve, a horizontally disposedcircular disc or plate 86 is shown extending outwardly therefrom. Ascanning lamp 87 is attached to the lower side of the circular disc nearits outer rim and extends downwardly therefrom. A detector photocell 88is also attached to the under side of the disc and is mounted within adetector photocell housing 89. A housing 91 is also disposed about thelamp, and is provided with a first horizontal slit 92 on the bottom sideof the housing, and a second vertical slit 93 on the inner wall of thelamp housing. The upwardly extending vertical wall 76 of the shield ispositioned between the scanning lamp 87 and detector photocell 88mounted on the scanning disc. A slit 95 is formed in the vertical wallof the shield. A case reference photocell 94 is mounted within a housing96 upon the inner wall of the instrument housing in a spaced relationwith the outer rim of the scanner disc and the lamp 87. Clearance isprovided between the reference photocell housing 96 and the lamp housing91. A slit 97 is provided in the top side of the case referencephotocell housing to permit light emanating from the lamp housing toimpinge upon the photocell 94.

An insulating block 98 is shown extending downwardly from the upper endof the instrument housing. The block holds horizontally disposed brushes99 therein for contacting commutator rings 100 on the scanning sleeve.Terminals 101 are connected to the brushes to provide electrical contactwith conducting wires (not shown) for supplying electrical power to thelamp and for transmitting a signal from the detector photocell toelectrical circuitry within the instrument. Likewise, suitable conductorwires are connected with the case reference photocell to provide a meansfor transmitting-a signal therefrom to such electrical circuitry withinthe instrument housing.

Operation of the gyro unit in the instrument is similar to thatdescribed above with respect to the pendulum units. The referencephotocell on the azimuth unit is lamp passes slit 97 to operatephotocell 94, the flip flop is triggered off. The pulses passed duringthis time span are indicative of azimuthal degrees of difference betweenMagnetic North and the reference photocell 94 on the gyro unit housing.

Directional unit 17 which houses the gyro and scan system describedabove also includes the encoder mechanism 21. Shaft 102 extends upwardlyfrom the motor 19 of the instrument for driving the encoder 21. Theoutput shaft from the motor is rotated at 3,600 rpm, or 60 revolutionsper second. The encoder is arranged to be run from the output shaft ofthe motor and to multiply such rotation of the output shaft as toprovide 12,000 pulses per second from the encoder.

The gear reduction section 79 is placed between the output shaft of themotor and the scanning device in the instrument housing so that thescanner is operated at 20 rpm or 1 revolution every 3 seconds.Therefore, when the scanning mechanism has made one revolution withinthe instrument housing, in 3 seconds, the encoder or pulse generator hasproduced 36,000 pulses. This relationship between the encoder pulses andthe scanner rotation readily permits a determination of degrees ofscanner rotation between signals from the first and second photocells toan accuracy of 0.01. It is also seen that synchronization between thescanning mechanism in the instrument and the pulses generated by theencoder prevents any variation in the power supply from affecting thereadout. Any variation in the operation of the motor from its intended3,600 rpm will provide a proportional relationship between therotational speed of the scanner and the output pulses from the pulsegenerator. The motor driving the angle detecting units is drivensynchronously with motor 19 and encoder pulses from encoder 21 are alsoprovided to circuitry for reading the angle units.

Referring now to FIG. 4 of the drawings, a schematic representation ofan electrical system for utilizing the information derived from theangle and azimuth units is shown. When pendulum 1 scans past the casereference photocell, the lamp on the pendulum activates the photocell,and causes it to send a signal to a case reference amplifier 106. Theamplifier shapes the signal and passes it to trigger on" a count controlflip flop 107. The flip flop 107 has a number of control functions.First, on the rise of the trigger on signal from the case referenceamplifier, that is, as the output of amplifier 106 rises to a positivepotential, the flip flop 107 sends an output signal to a count resetcircuit 108, which also is an amplifying and pulse shaping circuit. Theoutput of the count reset circuit is a 5 microsecond pulse that resetspendulum 1 binary counting units 113 to zero The 16 binary countingunits for receiving the output of pendulum 1 are in the form of a seriesof flip flops in ripple count configuration to provide a sixteen bitcounter.

A second control function of the count control flip flop 107 is toprovide a gate control signal to a pendulum 1 AND" gate 109. A secondinput to the pendulum l gate 109 is comprised of continuous pulses thatare generated by the pulse generator or encoder 21. The pulses from thepulse generator have been shaped in an amplifier and shaper circuit 110and multiplied at 112 so that the input frequency of pulses to the gateis 12,000 pulses per second. Therefore, when a signal is received fromthe count control flip flop 107 into the pendulum l gate 109, the gatewill pass the oncoming photocell 53 to send a signal to a pendulumdetector amplifier 111. This signal to the pendulum detector amplifieris passed to the count control flip flop 107 and causes the flip flop toturn off. This in turn removes the potential from one leg of thependulum 1 AND gate 109, causing it to stop passing pulses from thepulse generator to the pendulum 1 counting units.

At the time that the count control flip flop 107 turns 1 off, itsdecaying signal provides still a third control function. The decayingsignal activates a pendulum 1 store command circuit which is anamplifying and pulse shaping circuit. The output of the store commandcircuit is a five micro-second pulse that commands memory or storageunits 114 in association with the counting units to store all thecontents of the pendulum l counters. The storing units 114 are a seriesof flip flops slaved to look at information in the counter on commandfrom the pendulum storage command, and to store either a l or 0, that isa voltage or no voltage, which is present in the counter 113 at thetime. Thus, the counters are continuously gathering data from theinstrument units and on command, storing it.

This same sequence of the events described above is also taking place inthe circuitry associated with the second pendulum and the gyro, whichcircuitry is, in all significant respects, identical to that of thependulum circuit. After this sequence of events has taken place,meaningful data is stored in the memory or storage units of pendulum 1,pendulum 2, and the gyro, such storage being in either straight binaryor binary coded decimal form.

To review the operation of the electrical circuitry thus far described,the pendulum and gyro scanning systems provide a first signal uponactivation of a case reference photocell to pulse a count control flipflop 107. The output of flip flop 107 operates a gate 109 which whenoperated, passes pulses from pulse generator 21 to the ripple counter113. The scanning system then provides a second signal upon activationof a detector photocell. The second signal turns count control flip flop107 off and thus closes AND gate 109 to stop pulses to the ripplecounter 113. The decaying signal from the count control flip flop 107generates a signal in the store command circuit 115 which in turnactivates the storage units 114 to store the binary information in theripple counter. Thus every time the scanning system measures the angulardistance between the reference and detector photocells, pulses in timeproportion to such angular distance operate the ripple counter and thecount is then stored.

The method for relating such pulse count to angular measurement can beillustrated for example by reference to the pendulum l instrument. Whenthe scanning lamp passes the case reference photocell, the pendulum 1flip flop 107 is triggered on which in turn sends its output signal toAND gate 109. This output opens gate 109 to permit the passage of pulsesgenerated by the pulse generator 21 to the data count and storage units113 and 114 respectively. Such a signal from the flip flop 107 willcontinue until the lamp 48 on the scanner passes the slit 61 in thependulum shield to generate a signal from the detector photocell 53.This output passes through amplifier 111 to cause flip flop 107 to turnoff and thereby close gate 109. The gate will thus cease passing thepulses generated by the pulse generator to the data counter 113. Forexample, if the scanner lamp 48 takes I 95 seconds to move from thereference photocell to the detector photocell, the flip flop will beoutputting a signal for l 1% seconds. During this time span, 18,000pulses from the pulse generator will be passed by the pendulum l gate109 to the data counter 113. Since the scanner rotates at a rate of onerevolution every three seconds, the scanner will have moved in the l 1%seconds over an arc of 180.00, thus the detector photocell is located180 from the reference photocell. This indicates that the detectorhousing is in a vertical position, and that therefore the wellbore is ina vertically oriented position, since the slit 66 in the referencephotocell, which is at the top of the housing is in fact 180 away fromthe slit 61 in the pendulum shield which is located at the bottom centerof the pendulum.

Operation of the gyro unit in the instrument is similar to thatdescribed above with respect to the pendulum units. Since the gyro unitis referenced to the pendulum units and Magnetic North, the readingsfrom these units may be combined. to give a true angular and azimuthalorientation of the tool housing. First the outputs of the angle unitsare summed vectorially to provide an angle of inclination of thehousing.

Then, if the gyro unit output indicates that the housing has rotated Xdegrees from North, the pendulums have moved the same amount and thevector summation is likewise rotated X degrees. The resultantcomputation gives the angular disposition of the housing relative toMagnetic North or similar surface reference.

The next step is to transfer the information contained in the storageunits in a logical form over a single conductor cable that is also beingused to send high voltage 1 10 volt, 60 cycle power to the instrument.

Referring now to FIG. 5, the circuit used to transfer the informationstored in the memory of the system consists of 16 DC flip flops 116,also termed scan bits", which are arranged in a ring configuration. Onlythe first and last two flip flops are shown in block dia gram tosimplify the drawing. Of all flip flops, only one output can be high ata time, that is have voltage, while all the others will be low or atzero. When a clock pulse is fed to the scan bit circuits from a scandrive 117, the high output will sequence a step to the next flip flop. Ascan reset circuit 118 receives the line voltage and shapes a negativepulse for resetting portions of the circuit. One output of the scanreset is fed to the scan bit network. This output provides a triggerpulse to the ring configuration of flip flops to set a high output orone output as it may be called, on flip flop scan bit 1 and set theother flip flops to zero. Thereafter, the next clock pulse from scandrive 117 steps the one to scan bit 2, and the next clock pulse stepsthe one from scan bit 2 to scan bit 3, and so on through scan bit 16.The output of each individual flip flop 116 of the ring count is used asa gate signal to control the reading of the memory units of the penduluml and pendulum 2 units,

but for simplicity of the drawing and description, the gyro circuitryhas been omitted, it being substantially the same as that shown for thependulum units. The count and memory of each system consists of 16 bitsof binary information. We may think of each 16 bit section as a word,and of the three words as a frame. To simplify bit insertion or datainsertion on the power line, it is desirable to drive the 16 bit scannerwith the power frequency. This also synchronizes the data pulses withthe line frequency period. The reasons for this will be apparenthereinafter.

The system for reading out the information from the storage units 114comprises a word select programmer 121 for each of the separateinstrument sections, pendulum 1, pendulum 2, and gyro. Each of the wordselect programmers is a flip flop circuit. The programmers are arrangedin a ring count configuration similar to the scan bit circuit. Theresulting circuit is in the form of a three bit ring similar to the 16bit ring, but instead of selecting an individual bit, it selects anentire 16 bit word. The word select programmer receives its clock pulseor command to step to the next word from the decaying signal of the 16bit of the bit scanner. This decaying signal is provided from the 16 bitscan over a conductor path 122 to the individual word select programmers121. The scan reset circuit 1 18 also provides an output to the wordselect programmers for setting word select (pendulum 1) to ON whilesetting the other word select programmers to zero. Activation of thereset circuit 118 to reset the scan bit ring and the word select ringwill be described hereinafter.

Referring now to FIGS. 5 and 6 of the drawings, the circuit diagramshows a portion of the AC signal, which is used to power the instrumentbeing tapped off the line and sent to a bit filter circuit 126. The linesignal at this point has already been pulsed by data from the scan bitcircuit. (This operation will be described hereinafter). Therefore, inorder to use the line signal for other control purposes, it is in thiscase necessary to filter any bits of information or other spurioussignals and send a clean signal of power line frequency to the scandrive circuit 117. This so called clean signal is also sent to a wordgate drive circuit 127. The scan drive circuit is in the form of a pulseshaping circuit which is driven by the resulting sign wave from the bitfilter circuit 126. The scan drive circuit 117 removes the 60 cycle signwave, and in synchronism with the wave, places a narrow square wavepulse (one millisecond) on the line at plus This square wave pulse isfed to the scan bit ring counter to step the ring counter one step foreach pulse. The scan drive, in other words, selects the positive goingportion of the signal and shapes it into a one millisecond wide pulsethat occurs at 90 with respect to the 360 period of the signal. Thispulse occurs at every period of the line frequency and is used to drivethe 16 bit ring scan counter.

When power is first applied to the system, it causes the scan bit ringcounters 116 and the word select programmers 121 in ring countconfiguration to step through their entire sequence, this taking placein only a few milliseconds. Upon termination of the sequence in the wordselect programmers, a decaying signal from the gyro word selectprogrammer activates a sync pulse insert 128 which in turn drives thescan reset 118 to reset or turn on the word select for pendulum 1 andalso to provide a positive or one signal on scan bit 1. The sync pulseinsert 128 is a pulse shaping and amplifying circuit which sends asquare wave pulse to the scan reset 118. As will be described later, thesync pulse insert also places a sync pulse in the form of a spike on theline power.

The bit filter 126 also sends a portion of its output signal to the wordgate drive 127. The word gate drive is a pulse shaping circuit whichselects a negative going portion of the signal and shapes it into a onemicrosecond pulse that occurs on the negative portion of the linefrequency at 270 with respect to the 360 period of the signal. Thesepulses are occurring at the same frequency as those emerging from thescan drive 117 to drive the scanner, but they occur at different pointson the period of the line power. The pulses from the word gate drive 127are sent to word gates 130 which are two input AND gates associated witheach of the word select programmers. The signal from word gate drive 127is sent, for example, to the word gate drive for pendulum 1, which iscontrolled by the word select programmer 121 for pendulum 1. When theword select programmer output is positive, then a pulse from the wordgate drive is passed through the word gate 130 to a bit gate line 131,common to a bit gate 132, associated with each of the 16 bits.

Each of the bit gates has three inputs which are designated A, B, and C.If there is a voltage or ONE on input C which is derived from scan bit1, and if at the same time there is a voltage on input B from thestorage flip flop 114, that is if there is a ONE stored on the storageunit, then the two positive voltages on inputs B and C cause the bitgate 1 to open and pass the 270 positive square wave pulse from wordgate 130 through the bit gate 132 to a gate line drive path 133, andfrom there to a gate line bit insertion circuit 134. On the other hand,if either the scan bit 116 has a low voltage or zero, or if the storageunit 114 has a zero voltage, then the associated bit gate 132 does notpass the word gate pulse, so that no pulse is received on the gate linedrive at that point of time on the line signal. The scan drive 117 stepsthe scan bits from 1 through 16, with the same process taking place asset forth above so that when the gate bit associated with a scan bitsees a voltage in the associated storage unit, this causes a pulse fromthe word gate to pass on to the gate line drive and thus to the bitinsert 134. When all 16 bits of the pendulum No. 1 network have beenread, the decaying signal from scan bit 16 causes the word selectprogrammer to step to pendulum 2 and the process is repeated for the 16scan bits of pendulum 2 and so on.

The bit insertion circuit 134 is an amplifier that has in its output ahigh voltage PNP power transistor with a capacitive collector load 136in series with the high voltage line to the surface. The line voltagegoes negative at 270 so that a negative potential is available at thecollector of the power transistor. The negative square wave pulse at 270which was placed on the gate line drive to indicate information storedin the store and count section of the circuit is used to causesaturation of this transistor, which in turn causes a spike to appear onthe line at 270. In other words, the gate line bit insert circuit 134changes the square wave pulse at 270 to a spike, and superimposes it onthe power line 137 at the negative going portion of the sine wave, asshown by the diagrammatic sine wave on the line.

A similar means is used for inserting a synchronous pulse on the powerline at to enable a distinction between the starting and stopping pointsof a frame. Each frame is comprised of three series of 16 bit words fromeach instrument data storage section so that a frame as defined hereinis comprised of a beginning and ending sync pulse and 48 bitstherebetween.

Referring to FIG. 7 of the drawings, a schematic representation of theline signal is shown at A. Each period of the signal is considered onebit of information with the first 16 bits comprising the first word, andthe second 16 bits comprising the second word, etc., with the total of48 bits comprising three words, or one frame. Each frame begins and endswith a sync pulse 138 on the positive going portion of the wave. Thesync pulse insertion is accomplished with a pulse shaping and amplifyingcircuit 128 which generates a positive going square wave pulse at 90.This sync pulse has a dual function, one of which is accomplished byfeeding the pulse to the scan reset 118 (FIG. 6). The sync pulse circuit128 also is comprised of a transistor with a capacitive collector loadsimilarly to the gate line bit insert described hereinbefore. Thiscircuit similarly produces a synchronous pulse in the form ofa spikeexcept in this case a plus 90 position on to the power signal, whereindata spikes were positioned at 270 or a negative going portion of thewave form. The sync spike is shown in FIG. 7 on a positive going portionof the wave, and occurs at the beginning and end of the frame.

Referring again to FIG. 6, the square wave positive pulse which isformed by the sync pulse insert 128 in time relationship with the 90'position on the power signal is sent to the scan reset 118 to accomplishits second function. This pulse is transformed by the scan reset into anegatively going square wave pulse to reset the ring count circuits. Inother words, the signal from the scan reset 118 is sent to the wordselect programmers 121 and also to the scan bit flip flops 116. Thisoutput signal resets the scan bit ring by turning on the flip flop ofscan bit 1 and setting the others to zero. At the same time, the samesignal sets the word select programmer for pendulum 1 to an ON conditionand sets the other word select programmers to zero.

The sync pulse which initiates the sequence of events described aboveoriginates in the decaying portion of the signal from the word selectprogrammer in the gyro circuit. As the gyro circuit sequences from ahigh (which means data in the gyro memory is being read out) on itsoutput to a low on its output, the decaying signal is sent to the syncpulse insertion circuit 128. The sync pulse circuit 128 has as itsoutput an NPN power transistor with a capacitive collector load inseries with the line. This, as described above, triggers the NPNtransistor into saturation to cause a spike to appear on the positive 90portion of the power line frequency. Also, the pulse derived from thesync pulse insertion circuit is used to reset the circuits as describedabove to insure only one bit of the 16 bit scanner and three word selectscanner has an output or voltage at the start of each new scan. Whencircuit voltage is first applied to the scanner circuit, an output mayoccur on several of the flip flops, which would then be sequencedthrough the scanner ring. However, it is desirable for only one scan bitto have an output on each scanner. In order to provide this feature,upon turning on of the circuit, a

high or voltage will sequence through the gyro word select. The decayingportion of the high causes a sync pulse to be generated from the syncpulse insertion circuit 128 and put on the line. This sync pulse is alsosent from the sync pulse insert to the scan reset which sets a high intothe first scan bit and also into the first word select programmer.

The overall operation of the data storage and read out circuit describedabove may be described by way of example. If the word select programmer121 for pendulum l is high, (having a voltage thereon) the onemillisecond pulses occurring on each wave in time relation to the 270position, are presented to the bit gates 132.

v If the corresponding scan bit 116 is high and the memory storage ishigh, the l millisecond pulse (at 270) is passed onto the gate linedrive 133 as a one. If the memory storage is low, then a zero or nopulse (at 270") is passed onto the line. We thus pass onto the line acomposite signal consisting of the 60 second power frequency with datasuperimposed on the positive 90 portions .that relates to the framestart and stop, and data on the negative 90 (270) portions that relatesto the information stored within the system.

At the surface, the composite signal, represented by line A in FIG. 7,is passed through a data processing system as shown in FIG. 8 of thedrawings. Referring to FIG. 8, the line 137 from the subsurfaceequipment is shown connecting with a sine wave rejection circuit 141.The sine wave rejection circuit rejects the 60 cycle component of thesine wave to provide data pulses as represented by line "B" in FIG. 7.The resulting data pulses which are synchronous with 270 positions onthe line signal, and sync pulses at 90 are then sent to a dataprocessing circuit 142. In the data processing circuit the sync pulsesare separated from the data pulses by comparing the pulses with the linefrequency. Those pulses that occur on the positive 90 portion of thesignal are separated from those that occur on the minus 90 (270)portion, and put on separate lines.

The data pulses thus emerge from the data processing circuit on line 143as represented by line C in FIG. 7. The sync pulses on the other handemerge on line 144 as represented by line D in FIG. 7. The linefrequency is also fed to a clock or wave shaping circuit 146 whichshapes the negative 90 (270) portion of the line frequency into apositive going square wave pulse, as represented schematically on line147 and line E of FIG. 7. This square wave pulse is used as a clocksignal to shift the incoming data pulses on line 143 into a shiftregister 148. The shift register stores the binary data in the form itis received from the downhole count and store system thus retaining theidentity of the number counted by the system at the downhole location.The synchronous pulses emerging from the data processing circuit on line144 are used to reset the shift register to zero. The output from theshift register is sent to a storage system 151 within a computer 152 forperforming calculations on the accumulated data determinative ofborehole information.

The system described above provides new data on all three words (or anew frame) every three seconds. This data is in the form of 48 bits ofbinary information which is read out at a rate proportional to theperiod of the power line frequency. If the line frequency is 60 cyclesper second, which has a period of 16.6 milliseconds, then it takes 796.8milliseconds to read outfl all 48 bits of data in the memory and put inon the line. Since the scanner that reads the information is continu- Iously scanning we will get three read-outs approximately, of data fromeach scan. This non-destruct type of read-out is desirable for lookingat a series of readings and detecting any missing or added bits. Thecomputer for processing the data is programmed to look at the 3 databits read during each scan and compare the data bits. If there is adifference between the data bits, it rejects all of them, thuseliminating any error due to noise.

Although described with respect to surface recording, it is readily seenthat the apparatus described herein would be compatible for use withdownhole recording equipment for subsequent transmission to the surfacein a manner similar to that described herein. Therefore, whileparticular embodiments of the present invention have been shown anddescribed, it is apparent that changes and modifications may be madewithout departing from this invention in its broaderaspects, andtherefore, the aim in the above description is to cover all such changesand modifications as fall within the true spirit and scope of this Whatis claimed is:

1. In a position sensing and indicating apparatus for use in a boreholeand having a single conductor for supplying power from the surface tosaid apparatus and transmitting detected data to the surface, saiddownhole instrument means comprising; means for generating pulses andpassing said pulses into a circuit system; means for gateing the passageof said pulses into said circuit system in time relation with the mag:nitude of the detected parameter; means in said circuit system forcounting the pulses passed into said circuit system; and means fortransmitting said counted pulses to the surface over said singleconductor.

2. The apparatus of claim 1 and further including downhole means in saidcircuit system for storing said counted pulses as data.

3. The apparatus of claim 2 wherein said downhole instrument meansfurther includes data switching means responsive to the presence ofstored data for placing coded pulses on said single conductor, andsurface means for decoding said coded pulses to provide said data at thesurface.

4. The apparatus of claim 3 wherein said power for operating saidinstrument means is in the form of an al ternating current wave and saidcoded pulses are passed through said system in time relation with apredetermined position on the period of said wave.

5. The apparatus of claim 4 and further including data insertion meansfor placing an anomaly on said wave to form said coded data pulses. v

6. The apparatus of claim 5 and further including means for placing asecond anomaly on said wave at a different position relative to theperiod of said wave to produce a synchronization signal at the surface.

7. In apparatus for use in a borehole, downhole means for detecting aplurality of parameters in the borehole and transmitting detected datato the surface, said downhole means including single conductor means forsupplying power to said detecting means; means for generating pulses andpassing said pulses into a circuit system; means responsive to thedownhole detecting means for gateing the passage of pulses from saidpulse generating means into said circuit system in proportion to themagnitude of said detected parameters; means in said circuit system forstoring said counted pulses as coded data for each detected parameter;and means for sequentially transmitting the coded data from said storingmeans to the surface over said single conductor.

8. The apparatus of claim 7 wherein said storing means includes separatestorage sections for each detected parameter.

9. Apparatus for use in a borehole, including: means for detecting aplurality of wellbore parameters; means for connecting said detectingmeans with the surface; means for providing data pulses indicative ofeach of such parameters; means for storing a plurality of data bitsderived from said data pulses and representative of the magnitude of adetected parameter, with separate of such storing means being providedfor each parameter detected; scanning means for determining the presenceor absence of data bits within said storing means; and program means forsequentially applying said scanning means to such separate storingmeans.

10. The apparatus of claim 9' and further including means fortransmitting data signals representative of such scanned data bits tothe surface over said connecting means.

11. The apparatus of claim 10 wherein said connecting means includes asingle conductor cable which carries a power supply signal from thesurface to said detecting means.

12. The apparatus of claim 11 wherein said transmitting means includesmeans for superimposing said data signal on said power supply signal fortransmission to the surface over said single conductor cable.

13. The apparatus of claim 12 and further including means for generatingsynchronization signal, and means for superimposing said synchronizationsignal on said power supply signal at predetermined intervals to providedetectable divisions in the transmission of said data signals.

14. The apparatus of claim 13 and further including means fordifferentiating between said data signals and said synchronizationsignals, and means for recording said data signals.

15. The apparatus of claim 10 wherein said program means includes aplurality of gate means arranged in a configuration for repeatedlyoperating in sequence to apply said scanning means to such separatestoring means.

16. The apparatus of claim 15 and further including means responsive tothe operation of one of said gate means for generating a synchronizationsignal to be transmitted to the surface over said connecting means.

17. The apparatus of claim 9 and further including means for countingsaid data pulses and wherein said separate storing means are eachcomprised of a series of storage units for storing said data bits, saiddata bits being indicative of the number of such counted data pulses.

18. The apparatus of claim 17 wherein said scanning means sequentiallydetermines the presence or absence of data bits within said storageunits, and further including means for applying a data signal to saidconnecting means indicative of the presence or absence of the data bitswithin said storage units.

19. The apparatus of claim 18 wherein said connecting means includesconductor means for supplying a power signal to said borehole apparatus,and further including means responsive to the frequency variations ofsaid power signal for sequentially operating said scanning means andsaid program means.

20. The apparatus of claim 19 wherein said data signal is superimposedon said power signal at a position corresponding with one of thepositive and negative peak amplitudes of said power signal.

21. The apparatus of claim 20 and further including means responsive tothe sequential operation of said program means for superimposing asynchronization signal on said power signal at a position correspondingwith the other of the positive and negative peak amplitudes of saidpower signal.

22. The apparatus of claim 9 and further including a first series ofswitch means for operating said scanning means, a second series ofswitch means for operating said program means, and means responsive tothe last switch means in said second series for sequencing said firstand second series to the first switch means of each series.

23. The apparatus of claim 22 wherein said first and second series ofswitch means are comprised of an array of flip flops in ringconfiguration.

24. Apparatus for detecting wellbore parameters and passing signalsindicative of such parameters to the surface over a single conductor,including: downhole parameter detecting means; means for providing apower signal to the parameter detecting means; downhole circuit meansfor superimposing first and second signals on said power signal, saidfirst signal being time correlated with a particular portion of theperiod of said power signal and said second signal being time correlatedwith a different particular portion of the period of said power signal;surface means for separating said first and second signals from saidpower signal; and means for comparing said separated first and secondsignals with the period of the power signal to differentiate betweensaid first and second signals.

25. The apparatus of claim 24 and further including means forregistering said first and second signals in a manner indicative ofdetected wellbore parameters.

26. A method of detecting wellbore data and transmitting such data tothe earths surface, including the steps of: providing a power signal towellbore data detecting apparatus; detecting wellbore data; providingelectrical data signals indicative of such detected data; superimposingsuch data signals on the power signal to form a combined signal; suchdata signals being positioned on such power signal in a particular timedrelationship with the period of such power signal providing asynchronization signal which is positioned with respect to such powersignal in a different time spaced relationship with respect to theperiod of such power signal to provide a marker in said combined signalbetween data signal portions; passing such combined signal to thesurface; and comparing such combined signal with the power signal periodto separate such data signal from such combined signal.

27. The method of claim 26 and further including the step oftransforming such data signal into indicia determinative of detectedwellbore data.

28. The method of claim 26 wherein said synchronization signal is usedfor separating such data signal portions.

29. A method for detecting wellbore parameters and providing surfaceindications of such parameters, including the steps of: passing a powersignal from the surface to a downhole detecting system over a conductor;generating a series of downhole electrical pulses; gateing the passageof said pulses into an electrical system in proportion to the magnitudeof such detected parameters; counting the number of pulses gated intosuch electrical system; storing coded data indicative of the number ofcounted pulses in a data storage system; sequentially scanning such datastorage system for the presence of such coded data; providing datasignals indicative of such coded data; and passing such data signalsover such conductor to the surface.

30. The method of claim 29 and further including the steps of providinga synchronization signal, and passing such synchronization signal oversuch conductor to the surface for separating data signal portions.

31. The method of claim 30 and further including the steps of separatingsuch data signal and synchronization signal from such power signal atthe surface.

32. The method of claim 31 and further including the step of comparingsuch data signals and synchronization signal with such power signal todifferentiate such data signal and synchronization signal.

33. A method of measuring the angular and directional orientation of aborehole, including the steps of; suspending angular and directionalorientation measuring instruments in a borehole on a single con- 'ductorcable; passing a power signal to such instruments over the singleconductor cable; detecting angular and directional parameters of thewellbore; generating downhole signals indicative of such detectedparameters; superimposing such downhole generated signals on such powersignal in a predetermined timed relationship with the period of suchpower signal; and passing such superimposed signals to the surface overthe single conductor cable.

34. The method of claim 33 wherein the angular parameters measuredinclude the angular deviation from vertical of the instruments in planesto one another and further including the steps of separating thesuperimposed signals from the power signal to provide data indicative ofthe angular directional parameters; vectorially summing the angulardeviations; and applying directional parameters to such summation toprovide an accurate measure of the borehole orientation.

35. A method of measuring the directional characteristics of a borehole,including the steps of: placing a measuring instrument in the borehole,passing a power signal over a conductor path to the instrument in theborehole; generating signals in response to measured boreholecharacteristics, superimposing the generated signal on the power signalat a predetermined position with respect to the period of the powersignal to form a combined signal; passing such combined signal to thesurface over the conductor path; and comparing the combined signal withthe power signal to separate the generated signal indicative of boreholecharacteristics.

1. In a position sensing and indicating apparatus for use in a borehole and having a single conductor for supplying power from the surface to said apparatus and transmitting detected data to the surface, saId downhole instrument means comprising; means for generating pulses and passing said pulses into a circuit system; means for gateing the passage of said pulses into said circuit system in time relation with the magnitude of the detected parameter; means in said circuit system for counting the pulses passed into said circuit system; and means for transmitting said counted pulses to the surface over said single conductor.
 2. The apparatus of claim 1 and further including downhole means in said circuit system for storing said counted pulses as data.
 3. The apparatus of claim 2 wherein said downhole instrument means further includes data switching means responsive to the presence of stored data for placing coded pulses on said single conductor, and surface means for decoding said coded pulses to provide said data at the surface.
 4. The apparatus of claim 3 wherein said power for operating said instrument means is in the form of an alternating current wave and said coded pulses are passed through said system in time relation with a predetermined position on the period of said wave.
 5. The apparatus of claim 4 and further including data insertion means for placing an anomaly on said wave to form said coded data pulses.
 6. The apparatus of claim 5 and further including means for placing a second anomaly on said wave at a different position relative to the period of said wave to produce a synchronization signal at the surface.
 7. In apparatus for use in a borehole, downhole means for detecting a plurality of parameters in the borehole and transmitting detected data to the surface, said downhole means including single conductor means for supplying power to said detecting means; means for generating pulses and passing said pulses into a circuit system; means responsive to the downhole detecting means for gateing the passage of pulses from said pulse generating means into said circuit system in proportion to the magnitude of said detected parameters; means in said circuit system for storing said counted pulses as coded data for each detected parameter; and means for sequentially transmitting the coded data from said storing means to the surface over said single conductor.
 8. The apparatus of claim 7 wherein said storing means includes separate storage sections for each detected parameter.
 9. Apparatus for use in a borehole, including: means for detecting a plurality of wellbore parameters; means for connecting said detecting means with the surface; means for providing data pulses indicative of each of such parameters; means for storing a plurality of data bits derived from said data pulses and representative of the magnitude of a detected parameter, with separate of such storing means being provided for each parameter detected; scanning means for determining the presence or absence of data bits within said storing means; and program means for sequentially applying said scanning means to such separate storing means.
 10. The apparatus of claim 9 and further including means for transmitting data signals representative of such scanned data bits to the surface over said connecting means.
 11. The apparatus of claim 10 wherein said connecting means includes a single conductor cable which carries a power supply signal from the surface to said detecting means.
 12. The apparatus of claim 11 wherein said transmitting means includes means for superimposing said data signal on said power supply signal for transmission to the surface over said single conductor cable.
 13. The apparatus of claim 12 and further including means for generating a synchronization signal, and means for superimposing said synchronization signal on said power supply signal at predetermined intervals to provide detectable divisions in the transmission of said data signals.
 14. The apparatus of claim 13 and further including means for differentiating between said data signals and said synchronization signals, and means for recording said data signals.
 15. The apparatus of claim 10 wherein saiD program means includes a plurality of gate means arranged in a configuration for repeatedly operating in sequence to apply said scanning means to such separate storing means.
 16. The apparatus of claim 15 and further including means responsive to the operation of one of said gate means for generating a synchronization signal to be transmitted to the surface over said connecting means.
 17. The apparatus of claim 9 and further including means for counting said data pulses and wherein said separate storing means are each comprised of a series of storage units for storing said data bits, said data bits being indicative of the number of such counted data pulses.
 18. The apparatus of claim 17 wherein said scanning means sequentially determines the presence or absence of data bits within said storage units, and further including means for applying a data signal to said connecting means indicative of the presence or absence of the data bits within said storage units.
 19. The apparatus of claim 18 wherein said connecting means includes conductor means for supplying a power signal to said borehole apparatus, and further including means responsive to the frequency variations of said power signal for sequentially operating said scanning means and said program means.
 20. The apparatus of claim 19 wherein said data signal is superimposed on said power signal at a position corresponding with one of the positive and negative peak amplitudes of said power signal.
 21. The apparatus of claim 20 and further including means responsive to the sequential operation of said program means for superimposing a synchronization signal on said power signal at a position corresponding with the other of the positive and negative peak amplitudes of said power signal.
 22. The apparatus of claim 9 and further including a first series of switch means for operating said scanning means, a second series of switch means for operating said program means, and means responsive to the last switch means in said second series for sequencing said first and second series to the first switch means of each series.
 23. The apparatus of claim 22 wherein said first and second series of switch means are comprised of an array of flip flops in ring configuration.
 24. Apparatus for detecting wellbore parameters and passing signals indicative of such parameters to the surface over a single conductor, including: downhole parameter detecting means; means for providing a power signal to the parameter detecting means; downhole circuit means for superimposing first and second signals on said power signal, said first signal being time correlated with a particular portion of the period of said power signal and said second signal being time correlated with a different particular portion of the period of said power signal; surface means for separating said first and second signals from said power signal; and means for comparing said separated first and second signals with the period of the power signal to differentiate between said first and second signals.
 25. The apparatus of claim 24 and further including means for registering said first and second signals in a manner indicative of detected wellbore parameters.
 26. A method of detecting wellbore data and transmitting such data to the earth''s surface, including the steps of: providing a power signal to wellbore data detecting apparatus; detecting wellbore data; providing electrical data signals indicative of such detected data; superimposing such data signals on the power signal to form a combined signal; such data signals being positioned on such power signal in a particular timed relationship with the period of such power signal providing a synchronization signal which is positioned with respect to such power signal in a different time spaced relationship with respect to the period of such power signal to provide a marker in said combined signal between data signal portions; passing such combined signal to the surface; and comparing such combined signAl with the power signal period to separate such data signal from such combined signal.
 27. The method of claim 26 and further including the step of transforming such data signal into indicia determinative of detected wellbore data.
 28. The method of claim 26 wherein said synchronization signal is used for separating such data signal portions.
 29. A method for detecting wellbore parameters and providing surface indications of such parameters, including the steps of: passing a power signal from the surface to a downhole detecting system over a conductor; generating a series of downhole electrical pulses; gateing the passage of said pulses into an electrical system in proportion to the magnitude of such detected parameters; counting the number of pulses gated into such electrical system; storing coded data indicative of the number of counted pulses in a data storage system; sequentially scanning such data storage system for the presence of such coded data; providing data signals indicative of such coded data; and passing such data signals over such conductor to the surface.
 30. The method of claim 29 and further including the steps of providing a synchronization signal, and passing such synchronization signal over such conductor to the surface for separating data signal portions.
 31. The method of claim 30 and further including the steps of separating such data signal and synchronization signal from such power signal at the surface.
 32. The method of claim 31 and further including the step of comparing such data signals and synchronization signal with such power signal to differentiate such data signal and synchronization signal.
 33. A method of measuring the angular and directional orientation of a borehole, including the steps of: suspending angular and directional orientation measuring instruments in a borehole on a single conductor cable; passing a power signal to such instruments over the single conductor cable; detecting angular and directional parameters of the wellbore; generating downhole signals indicative of such detected parameters; superimposing such downhole generated signals on such power signal in a predetermined timed relationship with the period of such power signal; and passing such superimposed signals to the surface over the single conductor cable.
 34. The method of claim 33 wherein the angular parameters measured include the angular deviation from vertical of the instruments in planes 90* to one another and further including the steps of separating the superimposed signals from the power signal to provide data indicative of the angular directional parameters; vectorially summing the angular deviations; and applying directional parameters to such summation to provide an accurate measure of the borehole orientation.
 35. A method of measuring the directional characteristics of a borehole, including the steps of: placing a measuring instrument in the borehole, passing a power signal over a conductor path to the instrument in the borehole; generating signals in response to measured borehole characteristics, superimposing the generated signal on the power signal at a predetermined position with respect to the period of the power signal to form a combined signal; passing such combined signal to the surface over the conductor path; and comparing the combined signal with the power signal to separate the generated signal indicative of borehole characteristics. 